The applicant's successful and popular vehicle recovery system sold under the trademark LoJack® includes a small electronic vehicle locating unit (VLU) with a transceiver hidden within a vehicle, a private network of communication towers each with a remote transmitting unit (RTU), one or more law enforcement vehicles equipped with a vehicle tracking unit (VTU), and a network center with a database of customers who have purchased a VLU. The network center interfaces with the National Criminal Information Center. The entries of that database comprise the Vehicle Identification Number (VIN) of the customer's vehicle and an identification code assigned to the customer's VLU.
When a LoJack® product customer reports that her vehicle has been stolen, the VIN of the vehicle is reported to a law enforcement center for entry into a database of stolen vehicles. The network center includes software that interfaces with the database of the law enforcement center to compare the VIN of the stolen vehicle with the database of the network center which includes VIN corresponding to VLU identification codes. When there is a match between a VIN of a stolen vehicle and a VLU identification code, as would be the case when the stolen vehicle is equipped with a VLU, and when the center has acknowledged the vehicle has been stolen, the network center communicates with the RTUs of the various communication towers (currently there are about 180 nationwide) and progressively each tower transmits a message to activate the transceiver of the particular VLU bearing the identification code.
The transceiver of the VLU in the stolen vehicle is thus activated and begins transmitting its unique VLU identification code. The VTU of any law enforcement vehicle proximate the stolen vehicle receives this VLU transceiver code and, based on signal strength and directional information, the appropriate law enforcement vehicle can take active steps to recover the stolen vehicle. See, for example, U.S. Pat. Nos. 4,177,466; 4,818,988; 4,908,609; 5,704,008; 5,917,423; 6,229,988; 6,522,698; and 6,665,613 all incorporated herein by this reference.
Presently the VLU when activated sends a wideband e.g., 15 kHz signal with substantial data identifying the stolen vehicle. In Europe the wideband signal is somewhat lower e.g. approximately 11 kHz. When the VTU detects this, the officer in the tracking vehicle calls in the acquisition and then the VLU is triggered to begin transmitting more frequently e.g., from an initial rate of 4/min to the increased rate of 60/min. One shortcoming of this is that the wideband signal has a range of only about a mile. Thus the police cruiser with the VTU must generally be within a mile or so of the stolen vehicle to pick up the low band signal. Thus a larger number of VTUs are required to monitor a given area because of the short range.